• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.2
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• pp.75-82
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• 2020

The Daehang-ri intertidal flat located the just outside of the Saemangeum dike has been reported to show new-developing flats. Based on the topographic surveys of 21 times from 2000 to 2016 by a leveling method every year, this site clearly shows variation of deposition/erosion in time and space. Deposition has consistently occurred at the rate of +3.75 cm per year at the area along the dike (Zone 1), and this tidal flat is expanding and prograding seaward. In the area of far from the dike (Zone 2), on the other hand, erosion prevails at the rate of -2.38 cm per year, and this zone tends to retreat landward. However, the erosional trend of Zone 2 has slightly slowed down since 2014. As a whole from 2000 to 2016, net deposition is recorded over 3.0 m at the upper beach and the area adjacent to the dike (Zone 1), while erosion up to 1.0 m in Zone 2. In conclusion, the results at the Daehang-ri intertidal flat clearly revealed that its topographic changes were induced by the artificial structures and water masses through its sluice gate. Counter-clockwise gyre newly created after the sea dikes construction probably results in relocating of sediment outside the dike 1 by transportation of materials eroded from the south to the north along the coast.

• Land and Housing Review
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• v.6 no.2
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• pp.67-77
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• 2015

Now that it is the current situation that the smooth supply and demand are necessary for 2nd phase of beginning construction and stable development of Gaesung Industrial Complex, this study was willing to offer the planning criteria and model to establish the lodging for the workers in Gaesung Industrial Complex based on the agreement that both South and North Korea agreed in 2007. Regarding the plan, its standard and the alternative were reviewed considering welfare of workers, economic efficiency, technical validity, possibility of agreement and long-term development. The exclusive area per capita was calculated through Labor Standards Act of Korea and status survey of lodging for the workers provided to border line area between China and North Korea and the economic alternative based on one room for 6 persons with the public restroom was compared with that of development type based on one room for 4 persons with indoor restroom. Especially regarding the proposed site, the area with the optimized position was set by considering gradient, accessibility and convenience of development out of the area of Dongchang-ri where was agreed already and the priority of the proposed site that can keep the existing building site and provide was offered. The necessary period for whole construction was set as approximately 36 months. Regarding construction method, RC Rahmen method was selected as the optimized alternative considering the workmanship of manpower of North Korea and conditions of supply and demand of materials and cluster-type vehicle allocation plan based on 4~6 units considering the efficiency of supplying service facilities and convenient facilities along the simultaneous accommodation of 15,000 people was offered. It was analyzed that total business expenses of approximately 80~100 billion Korean Won would required though there were the difference for each alternative in the charged rental way that the development business owner develops by lending the inter-Korea Cooperation Fund and withdraws the rent by the benefit principle. The possibility of withdrawing the rent was analyzed assuming that the period of withdrawing the investment is 30 years. Especially for the operation management after moving, the establishment of the committee of operating the lodging for the workers of Gaesung Industrial Complex (tentative name) was offered with the dualized governance that the constructor takes charge of operational management, collecting fees and management of infrastructure and human resource management is delegated to North Korea.

• Plant Journal
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• v.15 no.4
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• pp.36-42
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• 2019

In recent, according to the tightening of environment regulation policy, the height of the site of the power plant is increased and the length of the cooling water pipe is increased. This has a serious impact on the stability of the plant. This study analyzes the transient phenomenon using LIQT 7.2, an unsteady state one-dimensional analysis software, to secure the stability of 1,000 MW high-capacity coal-fired power plant cooling water system with high head. To prevent water hammer, The effects on performance characteristics were predicted by individual and combination application. The surge pressure of the cooling water which occurs when the pump was stopped without installing the anti-surge devices was the largest at the pump outlet side. The most effective and simple way to reduce surge pressure in these cooling water systems is to combine a vacuum breaker with a hydraulic non-return valve, which is an essential device for pump protection.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.1
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• pp.1-8
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• 2015

Recently, constructions of coastal structure including wind turbine structure have increased at southwest shore of Korea. There is a big difference of tide which rage from 3.0 m to 8.0 m at south and wet shore of Korea, respectively. In such ocean circumstance, large scour may occur due to multi-directional tidal current and transverse stress of the wind. therefore scour surrounding wind turbine structure can make system unsafe due to unexpected system vibration. In this study, hydraulic resistance capacity, i.e., critical velocity and critical shear stress, was evaluated by RCT. Uni-directional and bi-directional hydraulic resistance capacities of the samples which were consolidated by different preconsolidation pressures were correlated with soil resistivities of same samples. According to the correlation, it is possible to estimate hydraulic resistance capacity from electrical resistivity of soil. Through the updating the correlation for various soil types, it is expected that the hydraulic resistance capacity of whole construction site will be simply determined from the electrical resistivity.

• Journal of the Korean GEO-environmental Society
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• v.13 no.12
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• pp.5-16
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• 2012

The second scientific antarctic station of South Korea is under construction at Terra Nova Bay located in eastern Antarctica. Ground condition in the Antarctica is frozen in general, but there are seasonal frozen grounds with active layers sporadically. When the active layer is frozen, frost heaving occurs that might cause the differential movement of frozen ground and the failure of structures. Therefore, it is necessary to determine the frost heaving susceptibility of soils at Terra Nova Bay before starting antarctic station construction. This study presents experimental investigation of the frost heaving susceptibility of soil samples with variation of particle sizes and unfrozen water contents. The soil samples were taken from five different locations at Terra Nova Bay and physical properties, unfrozen water content, and frost heaving tests were performed. For the frost heaving tests, soil specimens were frozen with constant freezing temperatures at the top and with drainage at the bottom in order to stimulate the frost heaving. The frost heaving tests provide volume expansion, volumetric strain, and heaving rate which can be used to analyze the relationship between the frost heaving vs. particle size and the frost heaving vs. unfrozen water content. Experimental results show that the more the fine contents exist in soils, the more frost heaving occurs. In addition, the frost heaving depends on unfrozen water content. Experimental data can be used to evaluate the frost heaving susceptibility of soils at the future construction site in the Antarctica.

• Korean Journal of Ecology and Environment
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• v.55 no.3
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• pp.231-243
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• 2022

Anthropogenic disturbances on freshwater ecosystem are known to degrade biodiversity, especially on fish assemblage. In this study, we have conducted fish surveys to identify impact of a bridge construction on fish assemblages. A total of eight study sites were surveyed in the Danjang and the Dong Stream in southern part of South Korea from June to November in 2021. The fish samplings were carried out five times, using cast-nets(10×10 mm mesh size), scoop-nets(4×4 mm, 5×5 mm mesh size), set-nets (10×10 mm mesh size), and fish traps (3×3 mm mesh size), along with the Stream/River Ecosystem Survey and Health Assessment by the Ministry of Environment of Korea and basic water quality measurement. Also, we applied the species diversity index and length-weight relationship regressions on certain species to identify interspecific growth rate differences in accordance with study sites. As a result, a total of 782 individuals, 23 species and 10 families were collected. The dominant species was Zacco Koreanus and relative abundance was 50.89%. When applying the length-weight relationship regressions on certain species, the 'b' value for Z. Koreanus was lower at the downstream points than at the upstream points of the construction site. In addition, when comparing to the results of the past survey, relative density of demersal fish at the upstream and downstream points decreased from 26% to 1.4%, and from 18% to 6.3%, respectively. In conclusion, it is considered that bridge construction negatively affects the habitat of fishes, especially on demersal fishes. Therefore, appropriate conservation efforts such as installation of silt protector and sand sedimentation pond are needed to alleviate the disturbance in habitat such as occurrence of turbidity and destruction of micro-habitats.

• Journal of the Korean Institute of Rural Architecture
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• v.22 no.3
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• pp.17-24
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• 2020

Reservoirs, which make up most of South Korea's reservoirs, are located in rural areas. In the case of rural reservoirs, about 75% have been reported over 50 years old aged reservoirs constructed before the 1960s. Reservoirs are important facilities that store and supply water necessary for daily life. However, if it is destroyed, the reservoir can cause a lot of damage, so continuous management is necessary. As a method for strengthening old reservoirs, a method using cement has been widely applied. However, OPC is a product that uses a lot of carbon dioxide and natural resources. Therefore, the amount of cement should be reduced. Against this background, in this study, the ground injection material of utilizing circulation resources was applied to the site. Applied reservoirs have been around for 75 years and leaks have occurred in some sections. The application method was constructed in two rows, up to a depth of 12m. After reinforcement, the electrical resistivity test was conducted three times. As a result, similar resistance was shown at 1 month after construction. And after 6 months, the saturation area decreased. And the performance after reinforcing the aged reservoir was examined. As a result of the review, this study confirmed that the applicability was equivalent to that of OPC, and the excellent performance of reinforcing the aged reservoir was shown.

• The Journal of the Convergence on Culture Technology
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• v.4 no.1
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• pp.253-261
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• 2018

Cheongpungho number is located in the center of South Korea Jecheon Peninsula, Chungju cheongpungho be formed by hydroelectric dam construction in 1984, now has been changed to a large man-made freshwater sites during the past 30 years. Recent Jecheon government is developing natural healing resort and entertainment performances for the future, in comparison to the feasibility study of the region using remote sensing technology and site planning was conducted in geographic research and analysis, and as a result, we have a very effective to incorporate the color maps using aerial photography and digital terrain analysis and usage analysis to prove and was in the riverside area for the future of the business and the research proposal facilities and events of the brand, to be more multi-cultural festival form apply new high-tech fusion experiments suggest new direction for future tourism.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.1
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• pp.109-116
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• 2024

The Rapid Hardening Composite Mat (RHCM) is a product that improves the initial strength development speed of conventional Geosynthetic Cementitious Composite Mats (GCCM). It offers the advantage of quickly securing sufficient strength in railway slopes with insufficient formation level, and provides benefits such as preventing slope erosion and inhibiting vegetation growth. In this study, an analysis of the practical applicability of RHCM in railway settings was conducted through experimentation. The on-site applicability was assessed by categorizing it into fire resistance, durability, and stability, and conducting combustibility test, ground contact pressure test, and daily displacement analyses. In the case of South Korea, where a significant portion of the territory is composed of forested areas, the prevention of slope fires is imperative. To analyze the fire resistance of RHCM, combustibility tests were conducted as an essential measure. Durability was assessed through ground contact pressure tests to analyze the deformation and potential damage of RHCM caused by the inevitable use of small to medium-sized equipment on the construction surface. Furthermore, daily displacement analysis was conducted to evaluate the structural stability by comparing and analyzing the displacement and behavior occurring during the application of RHCM with railway slope maintenance criteria. As a result of the experiments, the RHCM was analyzed to meet the criteria for heat release rate and gas toxicity. Furthermore, the ground contact pressure was observed to be consistently above 50 kPa during the curing period of 4 to 24 hours under all conditions. Additionally, the daily displacement analyzed through field site experiments ranged from -1.7 mm to 1.01 mm, confirming compliance with the criteria.

• Geophysics and Geophysical Exploration
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• v.13 no.4
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• pp.357-363
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• 2010

In this study, we investigated the geologic structure of the basement and overlying sediments of the construction site of the dinosaur egg fossil museum in Hwasung, Gyeonggi Province through refraction seismology, drilling, and downward seismic velocity measurements in the drill holes. The construction site ($350{\times}750\;m^2$) is located in the reclaimed area south of Sihwa Lake, Gojeong-ri. About 6,950 m of seismic refraction data consisting of 11 lines were acquired using a sledge hammer source. Drilling to the basement was performed at five sites. Sediment samples from drilling were analysed for grain-size distribution and age dating. At two drill holes, seismic velocity was measured with depth using a hammer as a seismic source. The geological structure of the study area consists of, from top to bottom, a tidal flat layer (5 ~ 12 m thick), a weathered soil layer (2 ~ 8 m thick), and the basement. The basement is interpreted as Cretaceous sedimentary rocks that tend to be shallow eastward. The volume of the tidal flat sediments and weathered soil in the study area is estimated as $1.4{\times}10^6\;m^3$, weighing $3.5{\times}10^6$ tons. The rate of sea level rise since 8,000 yrs BP is estimated to be 0.1 ~ 0.15 cm/yr.